Zoning System for Air Conditioning (HVAC) Equipment

ABSTRACT

A system for distributing conditioned air to a plurality of zones. The system includes an indoor heat transfer unit for thermally conditioning air and a plurality of fans which are operably connected to the indoor heat transfer unit to draw a volume of thermally conditioned air from the indoor heat transfer unit and direct the volume of the thermally conditioned air to a plurality of zones. The plurality of fans continuously monitor and control the volume of thermally conditioned air directed to each of the plurality of zones. Each of the plurality of fans are independently operable.

TECHNICAL FIELD

The present disclosure relates generally to a heating and air conditioning system, and more specifically to a multi-zone forced air heating and air conditioning system.

BACKGROUND

Controlling the volume of heated or cooled air distributed to different areas of a multiple zone system has been primarily accomplished with a VAV (variable air volume) damper system. VAV systems include a thermostat which is typically located in an occupied space and controls a damper, which limits the primary air flow from a central air handler. VAV systems are often deficient in that control of the air volume is managed by the damper, which creates a high pressure upstream of the damper and a lower pressure downstream of the damper. This lower downstream pressure is negatively affected by friction losses in ductwork, grills and diffusers which limit the VAV system's ability to efficiently distribute air to remote areas of the multiple zone system. Some systems seek to eliminate the duct losses downstream of the damper by locating the damper in the air outlet grille, but this complicates the control of the system and also creates the potential for increased noise as the velocity of the air increases locally as the damper closes.

Another deficient aspect of the VAV system is that the higher pressure on the upstream side can be considerable for the system to perform as designed, and thus creates energy loss. Due to the need for larger fan motor(s) in the central air handler, the VAV damper creates a restriction and the duct energy losses are increased with higher pressures and air velocities. Another disadvantage is the additional integrity provision needed on the high-pressure ductwork to reduce leaks. Modern VAV systems reduce these energy losses for part-load operation with variable speed operation of the central fan motor, but this further reduces the effectiveness of the downstream air distribution system. This strategy is further limited by the range of air flow required by conditioning system. There exists a need for an improved HVAC control system to improve efficiency and effectiveness for multi-zone systems.

SUMMARY

The disclosure describes a method for achieving air conditioning zones without restrictive dampers. The method dynamically adjusts the air balance of an air conditioning system to match the supply of conditioned air (i.e., air that has been conditioned to be hot or cold) to the thermal demands of the zones it serves. The method optimizes the effectiveness of an air conditioning system by directing the thermal capacity of the system to the zones requiring service without overcompensating in non-demanding zones.

In one aspect, the present disclosure relates to a system for distributing conditioned air to a plurality of zones. The system includes an indoor heat transfer unit for thermally conditioning air and a plurality of fans which are operably connected to the indoor heat transfer unit to draw a volume of thermally conditioned air from the indoor heat transfer unit and direct the volume of the thermally conditioned air to a plurality of zones. The plurality of fans continuously monitor and control the volume of thermally conditioned air directed to each of the plurality of zones. Each of the plurality of fans are independently operable.

In another aspect, the present disclosure relates to a method to automatically adjust the air balance of a heating ventilation and air conditioning system (HVAC). The method includes directing a measured volumetric rate of air through at least two adaptive distribution and control elements positioned remotely in at least two respective air circuit paths.

In still another aspect, the present disclosure relates to a system for distributing conditioned air to at least one remote zone. The system includes an indoor heat transfer unit for thermally conditioning air and at least one fan that is operably connected to the indoor heat transfer unit to draw a volume of thermally conditioned air from the indoor heat transfer unit and direct the volume of the thermally conditioned air to at least one remote zone. The at least one fan continuously monitors and controls the volume of thermally conditioned air directed to the at least one remote zone. The at least one fan is positioned remotely from the indoor heat transfer unit. The operable connection between the indoor heat transfer unit and at least one of the plurality of fans is damperless.

In still another aspect, the present disclosure relates to a method for distributing conditioned air to a plurality of zones. The method includes thermally conditioning a volume of air with indoor heat transfer unit. The method also includes drawing the volume of thermally conditioned air from the indoor heat transfer unit with a plurality of fans operably connected to the indoor heat transfer unit. The method also includes directing the volume of the thermally conditioned air to a plurality of zones with the plurality of fans. The plurality of fans continuously monitors and controls the volume of thermally conditioned air directed to each of the plurality of zones. Each of the plurality of fans is independently operable.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic block diagram of a conventional heating and air conditioning system, as is known in the art.

FIG. 2 is a schematic diagram of a conventional multi-zone variable air volume system, as is known in the art.

FIG. 3 is a schematic block diagram of a variable air flow heating and air conditioning system, according to an example embodiment of the present disclosure.

FIG. 4 is a schematic diagram of the variable air flow heating and air conditioning system shown in FIG. 3, as used in a structure.

DESCRIPTION OF EXAMPLE EMBODIMENTS

Common HVAC systems, for example as illustrated in FIG. 1, circulate conditioned air to a single zone inside a structure. The example system 10 also includes an indoor unit 20 and an outdoor unit 14. A thermostat control 16 is commonly located in the conditioned space in the air path near the return grille. The outdoor unit 14 can include a condensing unit and/or a heat pump unit. The heat transfer fluid (typically Freon, water, glycol, etc.) is transferred by piping line 18 from outdoor unit 14 to indoor unit 20.

Outside air supplied to the indoor unit 20 is commonly limited with a manual damper, but can also include an outside air control 26, such as a motor operated damper (not shown). In some examples, an outside air intake 12 can optionally be provided, particularly for newer code compliant installations. The indoor unit 20 can also include a filter (not shown), a heating-and-cooling coil 24 and a fan 22. Conventional indoor units 20 include the fan 22 positioned very close to the heating-and-cooling coil, commonly within the same housing or a directly connected housing forming an indoor unit, also called an evaporator or air handler. The indoor unit 20 is operably connected to an air path 28, such as a plenum and/or ductwork. The fan 22 directs hot or cool conditioned air from the indoor unit 20 into the air path 28. The air path 28, through the duct work and/or plenum, continues between the indoor unit 20 and a remote zone 30. The remote zone 30 includes a thermostat 32, which operably manipulates the desired temperature in the zone. In use, the heating-and-cooling coil in the indoor unit 20 adjusts the temperature of the air delivered to the supply air path 28 as the outdoor unit 14 cycles on and off under the control of the thermostat. The system 10 then includes a common return air path 34 to direct air from the remote zone 30 back to the indoor unit 20. The return air path 34 can include structures for directing air, such as grilles, ductwork and filters.

Systems such as the example illustrated in FIG. 1 can be reconfigured as a multi-zone system 100 in a structure such as a house 150, as illustrated in FIG. 2. The illustrated multi-zone system 100 includes an outdoor unit 104, and outside air control 126, an indoor unit 120 with a heating-and-cooling coil 124, a fan 122 and can optionally include an outside air intake 102. The heated or cooled air directed from the fan 122 is managed by a series of motor operated control dampers. The example dampers can be mounted in terminal units, also called VAV boxes 140 a-c, which limit the air flow to individual air paths 128 a-c. Each air path 128 a-c extends between a respective VAV box 140 a-c and a respective zone 130 a-c. Each VAV box 140 a-c controls the amount of heated or cooled air entering an air path 128 a-c from the fan 122.

A thermostat can be located in the space for each zone which provides control for each VAV box 140 a-c. An example thermostat located in the space for each zone can limit the amount of air directed through the air paths, thus providing a distinct temperature control for the three separate zones 130 a-c.

For this example, a common return is shown to provide an intake to ductwork, which returns the air path 142 from the zones 130 a-c to the indoor unit 120. Alternatively, individually ducted return air path schemes (not shown) can function similarly.

A VAF (variable air flow) system eliminates fans from the central air handler and also eliminates dampers, which creates conditioning zones. Each zone in the VAF system has a thermostat and is served by its own variable speed fan which pushes the air to its designated area through a standard system of ducts and diffusers. This distributed network of fans is controlled by a central controller which adjusts the speed of each individual fan to provide the volume of air flow to match the load of the zone it serves and it also maintains the net air flow through the heat transfer element of the air conditioning system which often has a specific range of operation. This VAF system moves the higher-pressure air flow downstream of the control mechanism to allow the system to overcome limitations imposed by the layout/geometry/configuration of conditioned space and provide for a more responsive system with less fan energy.

The VAF system includes a network of fans and an arrangement of ductwork to allow air to be pulled from an indoor heat transfer unit (IHTU) and distribute by a specific fan to the zone it serves. Essentially, the IHTU functions as an indoor unit without a fan. The fans are driven with variable speed motors to adjust the volume of air being provided to the zones. The fans have features and instrumentation to measure the volume of air being provided to the zones. Each zone has a thermostat which measures the temperature of the space and allows the occupant to enter the target (or set-point) temperature for the space. In addition to thermal inputs, the control system can account for schedule, occupancy, priority, relative humidity, and ventilation requirements (with instrumentation sensing items such as: Humidity, Occupancy, CO2, Indoor Air Quality, VOC, CO, etc.). The control system also maintains the total volume of air through the IHTU within the acceptable range of operation of the equipment. This air volume is further adjusted for system priorities such as humidity control, thermal accuracy, and energy efficiency.

An example VAF system 200 is illustrated in FIGS. 3 and 4. The VAF system 200 includes an outdoor unit 204 and an indoor heat transfer unit 205 (IHTU). The VAF system 200 can include a ventilation fan 203 drawing air from an outside air intake 202 and directing the outside air toward the IHTU 205. The ventilation fan 203 can have variable speed control, can measure air volume and can include CO₂ instrumentation and can form a part of an energy recovery scheme.

The VAF system 200 can connect the outdoor unit 204 to the IHTU 205 through at least one heat transfer fluid (typically Freon, water, glycol, etc.) transferred by piping line 211. The outdoor unit 204 can include a condensing unit and/or a heat pump, as well as a thermostat control.

The IHTU 205 can include a heating-and-cooling coil and a filter (not shown). The IHTU 205 does not include a fan. The VAF system 200 is divided into separate remote zones 230 a-c, for example three zones as illustrated in the example shown in FIGS. 3 and 4. Each zone 230 a-c has a separately-operable thermostat 232 a-c. In use, within the single VAF system 200 and the single IHTU 205, each separate zone 230 a-c can use a separate thermostat 232 a-c to maintain a different temperature in each zone. Separate air pathways 208 a-c, such as ductwork and/or diffusors, connect each zone 230 a-c to the IHTU 205. Each supply air pathway 208 a-c includes a separate fan 210 a-c positioned remote from the IHTU 205 along the air pathway. Each fan 210 a-c is activated to draw and direct conditioned air from the IHTU 205 along an air pathway 208 a-c to the respective zone 230 a-c. The VAF system 200 does not include or use balancing dampers to manage air flow from the IHTU 205.

In use, at least one of the thermostats 232 a-c creates demand to adjust the temperature in its respective zone 230 a-c. This demand for conditioned air causes one or more of the fans 210 a-c to activate to draw conditioned air from the IHTU 205 and direct the conditioned air to the respective zone(s) 230 a-c. Conditioned air from the IHTU 205 enters a common plenum (duct) 213 from which it then is drawn to a particular air pathway 208 a-c by fans 210 a-c as activated by the control system. Each thermostat 232 a-c causes one of the fans 210 a-c to move a measured volume of conditioned air from the IHTU 205 along one air pathway 208 a-c to a respective zone 230 a-c. As a result, one zone 230 a-c can adjust the temperature set-point independent from adjustments being made for the remaining zones while the remaining zones maintain their temperature in a dynamic and adaptive manner as loads and IHTU capacity varies.

The VAF system 200 can also include at least one return air vent 242 positioned in at least one of the zones 230 a-c to return air from the zones along a return air pathway to the IHTU 205 to be re-conditioned.

As particularly shown in FIG. 3, the VAF system 200 includes a central control 207, which communicates sensor inputs, including the temperature adjustment request and temperature reading between the thermostat 232 a-c in the zones 230 a-c and the fans 210 a-c. This information communicated through the central control 207 activates or deactivates dynamically increasing or decreasing the volumetric flow rate of the fans. The central control 207 communicates to the fans 210 a-c and the thermostats 232 a-c through electronic connection, wired or wireless, and can provide power to the fans. The central control 207 also performs the functions of a thermostat in the operational control of the outdoor unit 204 and IHTU 205, which is either in a heating mode or cooling mode. Transitioning from a heating or cooling mode can be determined in controls via a zone voting scheme, as used in some commonly offered VAV systems. The VAF system is not intended to function to provide for simultaneous heating and cooling in different zones. The VAF system functions to optimize the degree of control to each zone as demanded by the thermal loads of individual zones to better decouple the thermal load from the supply capacity of conditioned air provided by the outdoor unit 204 and IHTU 205. The central control 207 can also communicate with an outside air system in any of the schemes previously described and can incorporate input from sensors for humidity, CO₂, air quality providing power and control through electronic connection, wired or wireless. The central control 207 can also communicate with the outdoor unit 204 to activate or deactivate, and provide power through electronic connection, wired or wireless. The central control 207 can be in electronic communication with an operator interface 206, which allows a user to enter information such as set-points, schedules and priorities for the use of the VAF system 200.

The above disclosed system is illustrated, in FIG. 4 in particular, to be used in a house-like structure 250, but can be applicable to mobile as well as stationary installation., i.e. not just residential/commercial but also automotive (cars, buses, etc.), boats/ships, aircraft, etc. The described system can also provide diagnostic and analytic control, incorporating automated commissioning and advanced features which are not normally included in smaller systems.

Although specific embodiments of the disclosure have been described, numerous other modifications and alternative embodiments are within the scope of the disclosure. For example, any of the functionality described with respect to a particular device or component may be performed by another device or component. Further, while specific device characteristics have been described, embodiments of the disclosure may relate to numerous other device characteristics. Further, although embodiments have been described in language specific to structural features and/or methodological acts, it is to be understood that the disclosure is not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as illustrative forms of implementing the embodiments. Conditional language, such as, among others, “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments could include, while other embodiments may not include, certain features, elements, and/or steps. Thus, such conditional language is not generally intended to imply that features, elements, and/or steps are in any way required for one or more embodiments. 

We claim:
 1. A system for distributing conditioned air to a plurality of zones, the system comprising: an indoor heat transfer unit for thermally conditioning air; and a plurality of fans operably connected to the indoor heat transfer unit to draw a volume of thermally conditioned air from the indoor heat transfer unit and direct the volume of the thermally conditioned air to a plurality of zones, the plurality of fans continuously monitoring and controlling the volume of thermally conditioned air directed to each of the plurality of zones, each of the plurality of fans being independently operable.
 2. The system of claim 1, wherein each fan is in operable communication with a designated one of the plurality of zones so that a fan directs thermally conditioned air to only one of the plurality of zones and not any other of the plurality of zones.
 3. The system of claim 1, wherein each of the plurality of fans comprises a variable speed motor to control the volume of thermally conditioned air drawn from the indoor heat transfer unit and directed to one of the plurality of zones.
 4. The system of claim 1, wherein the operable connection between the indoor heat transfer unit and the plurality of fans is damperless.
 5. The system of claim 1, wherein the plurality of fans are remote from the indoor heat transfer unit.
 6. The system of claim 1, wherein the each of the plurality of fans directs the volume of thermally conditioned air to a different one of the plurality of zones than the other fans, directing the volume of thermally conditioned air via a system of ducts.
 7. A method to automatically adjust the air balance of a heating ventilation and air conditioning system (HVAC), the method comprising directing a measured volumetric rate of air through at least two adaptive distribution and control elements positioned remotely in at least two respective air circuit paths.
 8. The method of claim 7, wherein the measured volumetric rate of air is drawn from an indoor heat transfer unit by a variable speed fan and is distributed to a remote space in the air circuit path.
 9. The method of claim 8, wherein temperature control information is received from a plurality of control devices located in the remote spaces in their respective air circuit path.
 10. The method of claim 8, wherein the remote space is operably connected to the indoor heat transfer unit through a duct.
 11. The method of claim 8, wherein the variable speed fan draws and directs the volume of thermally controlled air without a damper.
 12. The method of claim 8, wherein a plurality of variable speed fans draw and direct volumes of thermally conditioned air from the internal heat transfer unit and toward the remote spaces, wherein each of the plurality of variable speed fans is operably connected to a different remote space such that one fan directs thermally conditioned air to one remote space.
 13. The method of claim 12, wherein each of the plurality of variable speed fans is controlled by the temperature control information received by one of a plurality of the independent control devices.
 14. A system for distributing conditioned air to at least one remote zone, the system comprising: an indoor heat transfer unit for thermally conditioning air; and at least one fan operably connected to the indoor heat transfer unit to draw a volume of thermally conditioned air from the indoor heat transfer unit and direct the volume of the thermally conditioned air to at least one remote zone, the at least one fan continuously monitoring and controlling the volume of thermally conditioned air directed to the at least one remote zone, the at least one fan positioned remotely from the indoor heat transfer unit, wherein the operable connection between the indoor heat transfer unit and at least one of the plurality of fans is damperless.
 15. The system of claim 14, wherein the at least one fan comprises a variable speed motor to control the volume of thermally conditioned air drawn from the indoor heat transfer unit and directed to the at least one remote zone.
 16. A method for distributing conditioned air to a plurality of zones, the method comprising: thermally conditioning a volume of air with indoor heat transfer unit; drawing the volume of thermally conditioned air from the indoor heat transfer unit with a plurality of fans operably connected to the indoor heat transfer unit; and directing the volume of the thermally conditioned air to a plurality of zones with the plurality of fans, the plurality of fans continuously monitoring and controlling the volume of thermally conditioned air directed to each of the plurality of zones, each of the plurality of fans being independently operable. 